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Development and Psychopathology 25 (2013), 14551472
# Cambridge University Press 2013
doi:10.1017/S0954579413000710
A quarter century of progress on the early detection and treatment
of autism spectrum disorder
GERALDINE DAWSONa AND RAPHAEL BERNIERb
aDuke University; and bUniversity of Washington, Seattle
Abstract
The last 25 years have witnessed tremendous changes in our ability to detect autism very early in life and provide interventions that can significantly influence
childrens outcomes. It was once questioned whether autism could be recognized before children had developed language and symbolic play skills; now
changes in early behaviors, as well as structural brain changes, have been documented in infants 612 months of age who later develop autism. Advances in
brain imaging and genetics offer the possibility of detecting autism before the syndrome is fully manifest, thereby reducing or preventing symptoms from
developing. Whereas the primary mode of behavioral intervention a few decades ago relied on operant conditioning, recent approaches integrate the methods of
applied behavioral analysis within a developmental, relationship-focused intervention model that are implemented by both parents and clinicians. These
interventions have been found to have positive effects on childrens developmental trajectory, as measured by both behavioral and neurophysiological
assessments. Future approaches will likely combine both behavioral and pharmacological treatments for children who have less robust responses to behavioral
interventions. There has been a paradigm shift in the way that autism is viewed, evolving from a lifelong condition with a very poor prognosis to one in which
significant gains and neuroplasticity is expected, especially when the condition is detected early and appropriate interventions are provided. The grand
challenge for the future is to bridge the tremendous gap between research and the implementation of evidence-based practices in the broader community, both
in the United States and worldwide. Significant disparities in access to appropriate health care for children with autism exist that urgently require advocacy and
more resources.
This 25th Anniversary Special Issue of Development and
Psychopathology provides an opportunity to look back at
the last quarter century of progress in autism research in the
areas of early detection and intervention with the goal of in-
forming future directions and priorities. The last two and a
half decades have involved significant changes in prevalence,
early detection, and intervention methods for autism spec-
trum disorder (ASD). In 1989, the prevalence of autism
was estimated to be 4 per 10,000 individuals, and 66% of
the autism population scored below 70 on standardized IQ
tests (Ritvo et al., 1989). In comparison, ASD is currently es-
timated to occur in about 1% of children in the United States
(1 in 88), with 1 in 54 boys affected. The distribution of in-
tellectual disability among individuals with ASD has also
changed significantly, with only 38% of individuals with ASD
The authors acknowledge Autism Speaks for its efforts in autism advocacy,
science, services, and awareness and the many families and individuals with
autism spectrum disorders, whose partnership in research has made the prog-
ress of the past 25 years possible. Elizabeth Sturdivant provided helpful edi-
torial assistance on this manuscript. This paper is dedicated to Dr. Marian
Sigman, mentor, colleague, and friend, whose pioneering efforts in the
area of developmental psychopathology transformed our understanding and
treatment of autism spectrum disorders.
Address correspondence and reprint requests to: Geraldine Dawson, De-
partment of Psychiatry and Behavioral Sciences, Duke University School of
Medicine, Durham, NC 27701; E-mail: [emailprotected]
now classified in the range of intellectual disability (IQ
70; Centers for Disease Control and Prevention [CDC],
2012). The reported increase in prevalence of ASD has been
demonstrated across multiple studies (Cavagnaro, 2009;
CDC, 2009, 2012; Hertz-Picciotto & Delwiche, 2009; King
& Bearman, 2009; Newschaffer, Falb, & Gurney, 2005). Al-
though it is clear that some of the increase in prevalence of
ASD is related to improved identification and broadening
definitions, a true increase in prevalence cannot be ruled out
(Rice et al., 2012). Current research is focusing on a variety
of prenatal and early postnatal environmental risk factors
that could help explain some of the increase in prevalence.
Multiple risk factors, including genetic and environmental
factors and their interaction, contribute to risk for autism
(Newschaffer et al., 2007).
Regardless of the reasons for the increases in prevalence, it
is clear that ASD now represents a major public health chal-
lenge. It is estimated that the annual cost of caring for indi-
viduals with ASD in the United States is $137 billion, with
the lifetime cost per individual estimated to be $2.4 million
for those with co-occurring intellectual disability and $1.4
million for those without intellectual disability (Buescher, Ci-
dav, Knapp, & Mandell, 2013). These estimates are based on
services and supports received, as well as opportunity costs
and productivity losses. Given that early detection and early
behavioral intervention has been shown to ameliorate the in-
tellectual impairment associated with autism, thus leading to
1455
mailto:[emailprotected]
1456 G. Dawson and R. Bernier
better long-term outcomes, improvements in the ability to
recognize autism early in life and access to effective interven-
tions can help reduce the costs of autism and increase quality
of life (Peters-Scheffer, Didden, Korzilius, & Matson, 2012).
This paper provides a perspective on the considerable prog-
ress that has been made over the past quarter of a century in
the ability to identify children at risk for autism and the devel-
opment of evidence-based early interventions that can lead to
improved outcomes. There has been a paradigm shift in the
way that autism is viewed, evolving from a lifelong condition
with very poor prognosis to one in which significant gains
and neuroplasticity is expected, especially when the condi-
tion is detected early and appropriate interventions are pro-
vided. The field of developmental psychopathology has
been a significant contributing factor in this shift in perspec-
tive on autism and long-term outcome, particularly in demon-
strating the dynamic and developmental nature of autism and
the important role of the environmental in shaping develop-
mental outcomes.
The Changing Landscape of Early Detection of Autism
Identification of autism in the 1980s
The landscape of early detection of autism has changed con-
siderably over the past quarter century. Formative work con-
ducted in the 1980s helped to define the core distinguishing
early characteristics of autism. This foundational understand-
ing set the stage for the systematic examination of autism in
infancy, originally through home videotape studies and
more recently through studies of high-risk infants, which
has led to tools for early screening. Looking ahead, the sci-
ence of early detection of autism will increasingly rely on
the use of genetics, neuroimaging, and other biomarkers.
There is a clear and significant increase in the ability
to diagnose autism at younger ages, with the current national
average age of diagnosis for children with autistic disorder
estimated to be 3.1 years of age (Mandell, Novak, &
Zubritsky, 2005). This shift can be largely traced back to
the seminal work conducted in the 1980s examining the early
distinguishing characteristics of autism from a developmental
psychopathology perspective. Only with the identification of
these key early features could we consider how autism may
look in early development and therefore develop methods
to accurately identify young children with autism. The foun-
dational work in identifying these early characteristics high-
lighted behaviors that were not necessarily part of the diag-
nostic nomenclature but that over the course of early
development would result in the social communicative im-
pairments that serve as the hallmark diagnostic criteria.
Pioneering work in the 1980s clarified the nature of the
impairments in affective reciprocity shown by young children
with autism. Although children with autism show similar fre-
quency and duration of facial expressions of positive affect
overall, they show less positive affect in conjunction with at-
tention to others, such as mothers and teachers, or when en-
gaged in interactions (Dawson, Hill, Spencer, Galpert, &
Watson, 1990; Kasari, Sigman, Mundy, & Yirmiya, 1990;
Yirmiya, Kasari, Sigman, & Mundy, 1989). It is this pattern
of intact positive affect in general but reduced facial expres-
sions in conjunction with engagement with others that con-
tributes to the impairments in affective reciprocity. Dawson
and colleagues (1990) coded videotaped observations of nat-
uralistic, face-to-face interactions between children with au-
tism and their caregivers. Raters unaware of diagnosis status
found that the frequency and duration of smiles and positive
affect did not differ between children with autism and typi-
cally developing peers but that the children with autism
were much less likely to combine smiles with eye contact
in acts to convey affective reciprocity (Dawson et al.,
1990). Further, although the groups did not differ in the fre-
quency with which they smiled at social (mothers verbaliza-
tion) and nonsocial (playing with a chair) actions, the chil-
dren with autism were much less likely to smile in response
to mothers smile than were the typically developing children.
In addition, results indicated that the mothers of the children
with autism smiled less frequently overall and in response to
their childrens smiles than did the mothers of the typical chil-
dren, highlighting a critical, developmental interaction: the
behavior of children with autism can influence the behavior
of those with whom they interact. Through careful and sys-
tematic coding of behaviors and facial expressions using
the Maximally Discriminative Movement Coding System,
Sigman and colleagues found that children with autism
were more neutral in their facial expressions and showed
more ambiguous facial expressions relative to typically devel-
oping children and children with mental retardation, thereby
disrupting the sense of emotional reciprocity (Yirmiya et al.,
1989). Further, coding of facial expressions elicited during a
semistructured interaction between a child and experimenter
in which joint attention and requests are elicited, the Early So-
cial-Communication Scales (Mundy, Sigman, Ungerer, &
Sherman, 1986) highlighted that when jointly attending to
toys or making requests of others, children with autism
show significantly less positive affect than typical peers or
peers with intellectual disability (Kasari et al., 1990). This
early work identified that although the display of affect over-
all differs little from comparison children, the affect displayed
during interactions with others is significantly impaired in au-
tism, highlighting the disruption to affective reciprocity in
young children with autism.
The observation that children with autism show marked re-
ductions in orienting to social information was another crit-
ical finding that helped improve early detection and establish
tools for screening young children with autism. Dawson and
colleagues documented a failure to orient to social stimuli and
introduced the term social orienting impairment as a core
early feature of autism. A social orienting impairment was
documented in preschool age children with autism (Dawson,
Meltzoff, Osterling, Rinaldi, & Brown, 1998) and subse-
quently noted in videotapes of 10-month-old infants who
go on to develop autism as well (Werner, Dawson, Osterling,
Early detection and treatment of autism spectrum disorder 1457
& Dinno, 2000). In the social orienting task, a child seated
across from an experimenter while playing quietly is pre-
sented with a series of auditory stimuli that are either social
(e.g., the childs name being called, clapping hands) or non-
social (e.g., car horn honking, kitchen timer). Using this para-
digm, Dawson and colleagues (1998) found that children
with autism more frequently failed to orient to all stimuli
on the social orienting task, with greater impairment for the
social stimuli compared to typical peers and children with
Down syndrome. Further, those children with autism who
oriented to the social stimuli were delayed in doing so relative
to the comparison children. Subsequent work examining so-
cial orienting in young children with autism has found that
impairments on the social orienting task, in conjunction
with impairments in joint attention, best discriminate children
with autism from their same age typically developing and de-
velopmentally delayed peers (Dawson, Toth, et al., 2004).
These and other findings led to the introduction of the social
motivation hypothesis (Dawson, Webb, & McPartland,
2005), which posited that autism is associated with reduced
social reward sensitivity that manifests in a failure to affec-
tively tag socially relevant stimuli. This failure to attend to so-
cial stimuli was further hypothesized to disrupt the neural and
behavioral development of a wide range of social and com-
municative skills, further compounding the impairments as-
sociated with autism (Dawson, 2008; Grelotti, Gauthier, &
Schultz, 2002).
Impairments in imitation were also viewed as a fundamen-
tal impairment that broadly affected social learning in young
children with autism. These imitation impairments were elu-
cidated through a series of studies that explored their preva-
lence and nature (Dawson & Adams, 1984; Rogers, Bennetto,
McEvoy, & Pennington, 1996; Rogers, Hepburn, Stack-
house, & Wehner, 2003). A deficit in joint attention, the abil-
ity to jointly share a common point of reference or coordinate
attention with a social partner, is another distinguishing char-
acteristic of children with autism that was influential in shap-
ing our understanding of autism and early detection efforts.
Mundy, Sigman and colleagues first demonstrated the critical
contribution of joint attention deficits to autism by comparing
children with autism to typically developing children and
children with intellectual disability and observing a much
lower frequency of sharing, showing, and pointing despite
similar general levels of responsiveness to their caregivers
among groups (Mundy et al., 1986). Further, they found these
deficits in nonverbal communicative behaviors, such as
pointing, better discriminated children with autism from the
comparison groups than did other behaviors, such as object
play. Finally, this early work highlighted the contributions
of joint attention behaviors to subsequent language develop-
ment in young children with autism (Mundy, Sigman, Un-
gerer, & Sherman, 1987). Research has shown that autism
is marked by impairments in initiating joint attention (i.e.,
spontaneously sharing and directing others attention), as op-
posed to requesting (Mundy et al., 1986) or responding to
joint attention bids (i.e., following others gaze and gestures
to share a common point of reference; Mundy, Sigman, & Ka-
sari, 1994). Further exploration of these deficits has revealed
that these impairments are consistent over time (Mundy, Sig-
man, & Kasari, 1990), correlate with subsequent language use
(Mundy et al., 1990), and are related to the intensity of subse-
quent social symptoms and outcomes (Mundy et al., 1994;
Sigman et al., 1999).
Subsequent experimental work examining young chil-
drens responses to others affective cues revealed differences
associated with autism. In a series of three experiments, Sig-
man and colleagues observed the behavior of children with
autism in response to experimenter and parent displays of dif-
ferent emotions and compared this to the behavior of children
with mental retardation and typical development (Sigman,
Kasari, Kwon, & Yirmiya, 1992). In the first experiment, ex-
aminers and parents pretended to hurt themselves with a plas-
tic hammer during play and then proceeded to display facial
and vocal expressions of distress. Overall the 3- to 4-year-
old children with autism often failed to notice or ignored
the affective displays of the adults, whereas the comparison
children were very attentive to the emotional displays, regard-
less of the type of affective display. Further, when the adults
showed a hurt expression, the children with autism were
much more likely to stay engaged with playing with a toy
than to attend to the adult in distress. Taken together with
findings on social orienting and joint attention, these findings
led to a general picture of autism involving a global impair-
ment in social attention (Dawson, Bernier, & Ring, 2012;
Dawson, Toth, et al., 2004).
Finally, within the last few decades, the notion of a deficit
in theory of mind was proposed and has played a key role in
the advancement of our understanding of the characteristics
of autism in children. By using Wimmer and Perners Sally
and Anne puppet scenario (Wimmer & Perner, 1983),
Baron-Cohen and colleagues demonstrated that, despite cog-
nitive ability greater than that of comparison children, chil-
dren with ASD failed to make inferences about anothers be-
liefs (Baron-Cohen, Leslie, & Frith, 1985). Charman and
Baron-Cohen further clarified that this deficit was specific
to the imputation of others mental states and beliefs and
not only a metarepresentation impairment by demonstrating
intact performance on false drawing but not false belief tasks
(Charman & Baron-Cohen, 1992). These studies identified
and clarified the disruption in theory of mind present in chil-
dren with ASD and underscored that autism is a disorder of
social cognition.
Concurrent to the illumination of the distinguishing char-
acteristics of children with ASD, examination of the early
manifestations of ASD in infancy was taking place. By col-
lecting home videotapes recorded by parents of children
who went on to receive an ASD diagnosis, these studies es-
tablished a relatively consistent picture of few symptoms ap-
parent at 6 months of age followed by a loss of social behav-
iors and the emergence of symptoms between 6 and 12
months. By coding behaviors observed on the videotape clips
of children who later were diagnosed with ASD and children
1458 G. Dawson and R. Bernier
with typical development while unaware of the childs diag-
nostic status, Osterling and Dawson (1994) found that chil-
dren with ASD, even at 1 year of age, showed a failure to ori-
ent to their name and demonstrated reduced eye contact,
pointing, and showing. Further, by examining these behav-
iors in first birthday party videotapes, Dawson and colleagues
were able to reliably distinguish children who subsequently
received an ASD diagnosis from those who later were diag-
nosed with intellectual disability without autism (Osterling,
Dawson, & Munson, 2002). Examination of videotapes of in-
fants between the ages of 8 and 10 months of age showed that
a failure to orient to name and reduced social smiling accu-
rately discriminated children with ASD from those with typ-
ical development (Werner et al., 2000). The findings from
these early studies highlighted the key early identifying fea-
tures of autism and underscored the idea that autism can be
reliably observed as early as the first year of life. The findings
that emerged from home videotapes, summarized by Ozonoff
and colleagues (Palomo, Belinchon, & Ozonoff, 2006) were
consistent with the first case study of an infant who was fol-
lowed prospectively from birth through diagnosis, which was
published in 2000 (Dawson, Small, Logan, & Geringer,
2000). The development of this infant was documented in
medical records made by a pediatric neurologist who noted
that the infant was socially engaged at 6 months but then be-
gan to withdraw and show distress reactions between 6 and 12
months. By 13 months of age, this toddler showed many
symptoms of autism and eventually received an autism diag-
nosis.
The identification of the early emerging distinguishing
characteristics of autism, such as deficits in joint attention
and affective reciprocity, paved the way for the development
of toddler screening tools. The Checklist for Autism in Tod-
dlers (CHAT) emerged as an early screening tool for autism,
which combined parent reports with clinical observation to
examine the presence or absence of these distinguishing au-
tism characteristics. Through nine short parent-report yes
and no questions and five short yes and no validation items
used by the clinician to cross-check the parent report, the
CHAT allows a clinician in the community to screen for
ASD in 18-month-old children in the typical population. In
a study of 91 18-month-old toddlers, 40 of which were
younger siblings of children with ASD, Baron-Cohen and
colleagues found that 4 of the 91 failed the CHAT, and of
the 4 toddlers that failed, all went on to receive a diagnosis
of ASD (Baron-Cohen, Allen, & Gillberg, 1992). Results
from a population-based study of the CHAT suggested that
screening of autism in the population is not only important
but also possible through quick assessment of the core behav-
iors first reported by seminal work in the 1980s highlighting
the social deficits in ASD (Baron-Cohen et al., 2000).
Current approaches to the identification of autism
Building on work conducted in the 1980s and 1990s, screen-
ing parameters were developed and implemented and a new
wave of screening tools was introduced in the community.
The American Academy of Neurology issued practice param-
eters highlighting a two-tiered screening approach in which
level 1 consists of routine developmental surveillance at all
well-child visits to identify children at risk for atypical devel-
opment, followed by identifying those specifically at risk for
autism, and Level 2 consists of formal diagnostic procedures
by expert evaluators (Filipek et al., 2000). In addition to the
recommendation that surveillance occur during all well-child
visits, the practice parameters stipulated that further evalu-
ation was required whenever a child failed to meet certain
milestones (babbling by 12 months, gesturing by 12 months,
using single words by 16 months, using spontaneous two-
word phrases by 24 months) if there was a loss of language
or social skills at any age. The practice parameters high-
lighted the importance of screening instruments, such as the
CHAT, for any child failing routine developmental surveil-
lance. More recently, the American Academy of Pediatrics
highlighted that although surveillance, the process of identi-
fying children at risk for developmental delay (Council on
Children With Disabilities, Section on Developmental Be-
havioral Pediatrics, Bright Futures Steering Committee, &
Medical Home Initiatives for Children With Special Needs
Project Advisory Committee, 2006), should be undertaken
in an ongoing manner at every visit, specific screening should
take place using an autism screening tool at 18 and 24 months
of age regardless of whether any risks have been identified
through ongoing surveillance (Johnson, Myers, & American
Academy of Pediatrics Council on Children With Disabil-
ities, 2007).
There are several screening measures for infants at Level 1
screening that are currently available to meet the American
Academy of Pediatrics recommendations: modified CHAT
(M-CHAT), the Pervasive Developmental Disorders Screen-
ing Test and the First Year Inventory and Infant Toddler
Checklist. The M-CHAT (Robins, Fein, Barton, & Green,
2001) and Pervasive Developmental Disorders Screening
Test (Siegel, 2004) offer Level 1 screening for toddlers,
which are parent-report screeners that provide clinicians
with key information through quickly completed question-
naires. The First Year Inventory (Baranek, Watson, Crais,
& Reznick, 2003) increases the lower age boundary for
screening through parent report of behaviors in children as
young as 12 months old. Level 2 screening measures include
the Screening Tool for Autism in Toddlers (Stone, Coonrod,
& Ousley, 2000) and the Communication and Symbolic Be-
havior Scales Developmental Profile (Wetherby & Prizant,
2002). Both are interactive tools that, in a 20-min play-based
interaction, provide the clinician with information regarding
the presence of autism along with key targets for intervention.
In addition to the short play-based interaction, the Communi-
cation and Symbolic Behavior Scales Developmental Profile
includes a general developmental screener, the Infant Toddler
Checklist, and a follow-up caregiver questionnaire.
At the same time that screening tools have increased in so-
phistication, so, too, has our understanding of early defining
Early detection and treatment of autism spectrum disorder 1459
characteristics of autism in young children. Studies of high-
risk infants, the younger siblings of children with ASD,
have painted a fuller yet more complicated picture of autism
in early childhood. The sibling recurrence rate of autism is
about 20%, much higher than the general population risk of
about 1% (Ozonoff et al., 2011). This makes this population
of high-risk siblings fertile ground for examining the early
emerging traits of autism. By following younger children
from very early on, 20% of whom will go on to develop
ASD, greater insight into the developmental course and tra-
jectory of autism can be gained. Even the 80% of siblings
who do not go on to develop ASD provide valuable contribu-
tions to our understanding of the disorder because many share
some of the characteristic features of ASD but to a lesser de-
gree, termed the broader autism phenotype. In this way, pro-
spective studies of at-risk infants provide a mechanism for in-
creasing our understanding of etiology and course as well as
enhance methods for early detection and indicate avenues for
intervention.
Prospective studies of high-risk infants are consistent with
the case study that was reported in 2000 showing that, during
the earliest months of life, young infant siblings exhibit only
subtle differences from low-risk infants, often displaying
clear social engagement (Ozonoff et al., 2010; Rogers,
2009; Tager-Flusberg, 2010). However, these prospective
studies demonstrate that by 12 months of age the young chil-
dren that ultimately develop ASD show notable differences
from those that do not. These children begin to show motor
delays (Landa & Garrett-Mayer, 2006), demonstrate unusual
repetitive behaviors (Iverson & Wozniak, 2007), display
atypical visual attention (Ozonoff et al., 2008) and disengag-
ing and shifting attention (Zwaigenbaum et al., 2005), as well
as display characteristic deficits in social communication,
such as reduced social orienting, joint attention skills, eye
contact, imitation abilities, and use of gestures (Mitchell
et al., 2006; Nadig et al., 2007; Ozonoff et al., 2010; Pres-
manes, Walden, Stone, & Yoder, 2007). However, despite
these clear differences observed at 1 year of age, there is no
one single atypical behavior that differentiates those children
who go on to develop ASD, reflecting the complexity of the
disorder and highlighting that it is the constellation of these
behaviors that indicates increased risk, not any one single be-
havioral deficit (Tager-Flusberg, 2010).
Even those young siblings who do not go on to develop
ASD show differences from low-risk comparison infants,
which suggests that these observed behavioral differences
could be phenotypic risk markers for autism, or endopheno-
types. Enhanced performance on working memory tasks fo-
cused on nonsocial stimuli (Noland, Reznick, Stone, Walden,
& Sheridan, 2010), increased latencies to disengage from a
central stimulus (Elsabbagh et al., 2009), decreased prefer-
ence for infant-directed speech (Nadig et al., 2007), reduced
affective facial expressions (Yirmiya et al., 2006), and re-
duced smiling (Cassel et al., 2007) have all been observed
in high-risk younger siblings relative to low-risk younger sib-
lings. Recent work suggests that 19% of high-risk siblings
who do not go on to develop ASD by 3 years of age show
the presence of broader autism phenotype traits by 1 year of
age (Georgiades et al., 2013).
The development of the Autism Observation Scale for In-
fants (AOSI) stemmed from the work on infant siblings. The
AOSI was initially designed to identify and monitor early
emerging autism signs as observed in high-risk infant siblings
of children with ASD (Bryson, Zwaigenbaum, McDermott,
Rombough, & Brian, 2008). The goal of its development
was to provide developmentally appropriate activities for in-
fants so that through 20 min of direct play interaction and cod-
ing behaviors in several domains, putative signs of autism can
be detected. The interactive approach requires an examiner
skilled with both infants and autism to administer a series
of presses during the interactive play through which behav-
iors in the social, affective, communication, visual, and motor
domains can be coded. The contribution of this measure to
our understanding is underscored by findings resulting from
its use. Longitudinal studies utilizing the AOSI has revealed
increased repetitive motor mannerisms in at-risk siblings at
12 and 18 months (Loh et al., 2007), differences in sensory
responsivity evidenced at 12 months (Zwaigenbaum et al.,
2005), atypical levels of behavioral activity and motor control
(Brian et al., 2008), and increased presence of the broader au-
tism phenotype in high-risk siblings who do not develop
ASD (Georgiades et al., 2013).
The work of the last few decades ultimately paved the way
for the development of screening instruments and tools to
identify and diagnose autism earlier and earlier. The study
of at-risk, younger siblings of children with autism has
yielded critical information leading to breakthroughs in our
understanding of early symptom emergence and course and
development of ASD and has provided insight into etiologi-
cal mechanisms. Recent advances in technology and genetics
suggest that we are on the crest of a wave of advances in our
ability to detect autism through the use of biomarkers and
new screening tools.
Looking ahead
The future of the early identification of autism will see in-
creased application of neuroimaging and genetics. The iden-
tification of biomarkers for autism is a high priority for the
scientific community; the National Institutes of Health Inter-
agency Autism Coordinating Committee Strategic Plan calls
for the identification of biological markers that separately, or
in combination with behavioral markers, accurately identify,
before age 2, one or more subtypes of children at risk for de-
veloping ASD (Interagency Autism Coordinating Commit-
tee, 2011). Developmental perspectives increasingly incorpo-
rate multiple levels of analysis (Cicchetti & Dawson, 2002) as
a means of exploring the early indices of autism.
Electrophysiological studies of toddlers and preschoolers
with ASD have demonstrated the utility of the study of
event-related potentials (ERPs) and electroencephalography
(EEG) in elucidating differential brain activity in infants
1460 G. Dawson and R. Bernier
with autism. Because electrophysiological paradigms do not
rely on language or behavioral responses beyond passive
viewing they are excellent for studying neurophysiological
processes in infants. EEG, with its temporal sensitivity, pro-
vides insight into aspects of brain activity that functional
magnetic resonance imaging studies are unable to illuminate.
ERPs, which can be derived from EEG recordings, reflect the
averaged brain response to the repeated presentation of a sin-
gle stimulus event. Atypical ERPs have been observed in
young children with autism in response to the observation
of faces and facial expressions (Dawson et al., 2002;
Dawson, W
